204 The Lije Story of the Fish 



scription has shown a discrepancy in the number of rays in 

 the dorsal and anal fins, and raises strong doubt whether 

 this actually was a tarpon. 



If the tarpon does have a leptocephalus stage, why has it 

 never been found, when this stage in the ten-pounder is 

 common? The fate of the little fish hatched from the hypo- 

 thetical "tarpon" eggs in the laboratory provides a clue to 

 the answer. The water in which they were held, taken from 

 the nearby shore, was found to be full of minute crustaceans 

 which were so voracious that they set upon the little fish and 

 devoured them as soon as they were out of the t.^g^ and it 

 was impossible to raise them even to three days of age with- 

 out first filtering out these predators. The "green" inshore 

 water where the tarpon have been seen to spawn is also alive 

 with these crustaceans j the "blue" outside waters are almost 

 devoid of them. In these "blue" waters larval stages of other 

 known fish have been found whkh are absent from the in- 

 shore waters. Piecing all of these facts together, the follow- 

 ing hypothesis emerges: Little tarpon which hatch in the 

 "green" water succumb to the tiny crustacean predators. 

 However, the smooth round eggs are immune to such at- 

 tacks} if some of these are carried by currents into the "blue" 

 water before hatching (and in the denser "blue" water they 

 float), the larval tarpon then have a chance to survive. Or, it 

 may be that adult tarpon spawn in the "blue" water as well 

 as in the "green." That the larval tarpon has a leptocephalus 

 stage and that this stage is passed in the "blue" waters is the 

 conjecture which fills in the gap in our knowledge. The fact 

 remains, however, that neither in these "blue" waters nor 

 anywhere else has anything been found which could be posi- 

 tively identified as a larval tarpon. 



With the very doubtful exception of the Beaufort speci- 

 men, tarpon under two inches long have never been seen. 

 From two to eight inches, numerous individuals have been 



